EP0404211A1 - Procédé pour commander la libération de couches intermédiaires enclavées - Google Patents

Procédé pour commander la libération de couches intermédiaires enclavées Download PDF

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Publication number
EP0404211A1
EP0404211A1 EP90201074A EP90201074A EP0404211A1 EP 0404211 A1 EP0404211 A1 EP 0404211A1 EP 90201074 A EP90201074 A EP 90201074A EP 90201074 A EP90201074 A EP 90201074A EP 0404211 A1 EP0404211 A1 EP 0404211A1
Authority
EP
European Patent Office
Prior art keywords
fracturing fluid
breaker
scavenging material
hydrocarbons
production
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP90201074A
Other languages
German (de)
English (en)
Inventor
Janet Gulbis
Trevor D.A. Williamson
Milton T. King
Vernon G. Constien
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PUMPTECH NV
Compagnie des Services Dowell Schlumberger SA
Original Assignee
PUMPTECH NV
Compagnie des Services Dowell Schlumberger SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PUMPTECH NV, Compagnie des Services Dowell Schlumberger SA filed Critical PUMPTECH NV
Publication of EP0404211A1 publication Critical patent/EP0404211A1/fr
Withdrawn legal-status Critical Current

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/60—Compositions for stimulating production by acting on the underground formation
    • C09K8/92—Compositions for stimulating production by acting on the underground formation characterised by their form or by the form of their components, e.g. encapsulated material
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/60—Compositions for stimulating production by acting on the underground formation
    • C09K8/62—Compositions for forming crevices or fractures

Definitions

  • the invention relates to improved fracturing fluids containing an encapsulated breaker and an improved method of fracturing subterranean formations penetrated by a wellbore using these fracturing fluid systems containing a breaker.
  • a common method of increasing productivity of a hydrocarbon-bearing formation is to subject the formation to a fracturing treatment.
  • This fracturing treatment is produced by injecting a liquid, gas, or two-phase fluid, which is generally referred to as a fracturing fluid, down the wellbore at a sufficient pressure and flow rate to fracture the subterranean formation.
  • a proppant material such as sand, fine gravel, sintered bauxite, glass beads and the like can be introduced into the fracture to keep it open.
  • the propped fracture provides larger flow channels through which an increased quantity of hydrocarbon can flow, thereby increasing the productivity of the well.
  • breakers may be used to reduce fluid viscosity and promote the return of the fracturing fluid to the wellbore. It is desirable that the breaker not affect fluid viscosity during pumping, but rapidly reduce fluid viscosity after pumping is completed.
  • breakers such as enzymes and persulfates currently used in fracturing fluids do not produce the desired viscosity profile. Enzymes, for example, begin to reduce fluid viscosity immediately. Persulfate breakers, on the other hand, react very slowly at surface temperatures. The reaction rate increases with temperature so that after the fracturing fluid reaches about 60°C (140°F), the reaction between the persulfate and fracturing fluid goes rapidly causing premature viscosity loss.
  • U.S. Patent 4,741,401 describes a method of delaying the time at which an aqueous fracturing composition will break by encapsulating the breaker in a water-insoluble, essentially water-impermeable material which, after sufficient exposure to the fracturing fluid, will rupture and release the breaker.
  • U.S. Patent 4,552,675 describes a method of delaying the time at which an aqueous fracturing composition will break by adding an organic hydroxyl free radical scavenger such as allyl alcohol, catechol, and 1,10-orthophenanthroline to retard the action of a peroxygen breaker.
  • an organic hydroxyl free radical scavenger such as allyl alcohol, catechol, and 1,10-orthophenanthroline
  • U.S. Patent 4,506,734 describes a method of delaying the time at which an aqueous fracturing composition will break by encapsulating the breaker within hollow or porous, crushable beads made from glass, ceramics, plastics, gels, or mixtures thereof.
  • U.S. Patent 4,202,795 describes a method of delaying the time at which a high viscosity aqueous gel or emulsion will break by encapsulating the breaker in a hydratable gelling agent which forms a protective gel around the breaker.
  • the present invention provides fracturing fluid composition which includes: a fracturing fluid; an encapsulated breaker which is released into the fracturing fluid under a predetermined time/temperature condition to reduce the viscosity of the fracturing fluid; and a scavenging material contained in the fracturing fluid for reacting with any breaker released into the fracturing fluid before said predetermined time/temperature condition.
  • a predetermined time/temperature condition is a predetermined time and/or temperature condition or a stress condition caused by fracture closure at which an operator intends to release breaker into a fracturing fluid to reduce the viscosity of the fracturing fluid.
  • the scavenging material prevents the breaker from prematurely reacting with the fracturing fluid polymer to reduce the viscosity of the fracturing fluid.
  • the present invention also allows a reduced coating thickness of encapsulating material surrounding the breaker.
  • the encapsulated breaker/scavenger system of the present invention may be used with linear and crosslinked aqueous fracturing fluids to provide both maximum viscosity during pumping and rapid viscosity decline after pumping stops.
  • the release rate of the encapsulated breaker varies with temperature, so the scavenger concentration is preferably adjusted for temperature and pump time.
  • the overall composition of the fracturing fluid solution is important to the success of the scavenger. To be effective, the scavenger should react faster with the breaker than the breaker reacts with the fracturing fluid polymer.
  • a preferred fracturing fluid for use as the base of the solution is guar or hydroxyproplguar (HPG).
  • HPG hydroxyproplguar
  • the fracturing fluid base is present at a concentration of between about 20 and about 70 lb/Mgal, more preferably at a concentration of from about 30 to about 50 lb/Mgal.
  • the fracturing fluid solution may also contain one or more antifoam agents, bactericides, surfactants or an acid or a base to adjust pH.
  • the solution preferably contains a salt such as KCl at a concentration of from about 0.5 to about 5; most preferably 2% by weight.
  • SDD is a much more effective scavenger for APS in the presence of KCl.
  • Other salts which might be beneficial are NaCl, MgCl2, CaCl2, NH4Cl, KI, and KBr.
  • the encapsulated breaker is generally used at a concentration of from about 0.1 to about 50 lb/Mgal (active) and preferably at a concentration from about 1 to about 10 lb/Mgal.
  • the amount of breaker scavenged is generally from about 1 to about 30%, preferably from about 1 to about 20%.
  • concentration of scavenger will depend on the breaker used, but should range from about 0.01 to about 30 lb/Mgal, preferably from about 0.1 to about 10 lb/Mgal.
  • the preferred weight ratio of SDD to released persulfate is approximately 1 to 1. See Figures 3 and 4.
  • the scavenger material employed should react rapidly with the breaker to prevent it from reacting with the fracturing fluid polymer.
  • the gelling agent used in the fracturing fluid is guar or hydroxypropylguar (HPG) and the breaker is ammonium persulfate
  • the preferred scavenger is sodium dimethyldithiocarbamate (SDD).
  • SDD is used in combination with an encapsulated breaker of ammonium persulfate coated with polyvinylidene and methylmethacrylate copolymer (PVDC).
  • guar-PVDC/ammonium persulfate-SDD system While a guar-PVDC/ammonium persulfate-SDD system is described above, the utility of the polymer-encapsulated breaker-scavenger system of the invention is not limited to this embodiment.
  • another suitable scavenger for the purposes of the invention is sodium thiosulfate as shown in Figure 5.
  • Triethanolamine may also be used as a scavenger, especially when KCl is not present in the fracturing fluid solution. See Figures 6 and 7.
  • Peroxygen breakers useful in the practice of the present invention include sodium perborate, sodium carbonate peroxide, hydrogen peroxide, potassium diperphosphate and salts of monopersulfuric and dipersulfuric acid. It is generally preferable to use a peroxygen compound selected from ammonium and alkali metal salts of monopersulfuric acid and ammonium and alkali metal salts of dipersulfuric acid, alkali metal diperphosphates, t-butylhydroperoxide and hydrogen peroxide.
  • Other breakers useful in the practice of the present invention include hypochlorite salts such as alkali metal hypochlorite salts, transition metal ions such as Fe+2 and Cu+2, and acids with a pKa less than 4. Suitable acids include sulfamic, hydrochloric and oxalic.
  • Gelling agents on which fracturing fluids may be based in the practice of the present invention include hydratable polysaccharides, polysaccharide derivatives, polyacrylamides, polyacrylamide copolymers, and polyvinyl alcohol.
  • other suitable fracturing fluids may include thickeners such as CMHPG and other guar derivatives, hydroxyethylcellulose (HEC), carboxymethyl hydroxyethylcellulose (CMHEC) and other cellulose derivatives, polyacrylamides and heteropolymers thereof, xanthan gum, and surfactant systems.
  • Table I illustrates useful combinations of breakers, gelling agents, and scavengers. Using the method described above, other useful combinations may be readily determined.
  • Table II illustrates the effect of scavengers according to the present invention with respect to a sodium hypochlorite breaker. These examples illustrate the effectiveness of the compositions and methods in the present invention in maintaining the viscosity of fracturing fluids in the presence of premature breaker release.
  • a base fluid solution was prepared which contained 60 lb HPG/Mgal, an antifoam agent, a bactericide and a surfactant in 2% KCl aqueous solution.
  • the pH was adjusted to 9.5 with Na2CO3.
  • Samples containing breaker, encapsulated or unencapsulated, and scavenger were added to glass bottles and placed in a shaker bath set at 80°C (175°F). At hourly intervals, the samples were removed, cooled and the viscosity measured at ambient temperature (24°C, 75°F).
  • Figure 1 illustrates the benefit of encapsulation and the greater benefit of combining an encapsulated breaker with a scavenger. It also illustrates the cost-saving benefit of using a low level of coating plus a scavenger. The 20% coating plus scavenger system performs similarly to the 45% coating system, but is significantly less expensive.

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Agricultural Chemicals And Associated Chemicals (AREA)
EP90201074A 1989-05-01 1990-04-27 Procédé pour commander la libération de couches intermédiaires enclavées Withdrawn EP0404211A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US34549289A 1989-05-01 1989-05-01
US345492 1989-05-01

Publications (1)

Publication Number Publication Date
EP0404211A1 true EP0404211A1 (fr) 1990-12-27

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EP90201074A Withdrawn EP0404211A1 (fr) 1989-05-01 1990-04-27 Procédé pour commander la libération de couches intermédiaires enclavées

Country Status (4)

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EP (1) EP0404211A1 (fr)
AU (1) AU5399590A (fr)
BR (1) BR9001977A (fr)
NO (1) NO901934L (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0677642A2 (fr) * 1994-04-12 1995-10-18 Halliburton Company Procédé pour la rupture de fluides viscosifiés dans un puit de pétrole

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3760881A (en) * 1971-05-24 1973-09-25 Exxon Production Research Co Treatment of wells with fluids containing complexes
US3779914A (en) * 1971-05-20 1973-12-18 Dow Chemical Co Composition of improved viscosity control and method of use
US3818991A (en) * 1971-05-20 1974-06-25 Dow Chemical Co Method of treating subterranean formation with a composition of improved viscosity control
US4202795A (en) * 1978-09-28 1980-05-13 Halliburton Company Methods and additives for delaying the release of chemicals in aqueous fluids
US4436156A (en) * 1982-06-21 1984-03-13 Halliburton Company Method of treating well formations employing foamed treatment fluids
US4506734A (en) * 1983-09-07 1985-03-26 The Standard Oil Company Fracturing fluid breaker system which is activated by fracture closure
US4552675A (en) * 1983-08-19 1985-11-12 Fmc Corporation Composition and method for treating a subterranean formation
US4741401A (en) * 1987-01-16 1988-05-03 The Dow Chemical Company Method for treating subterranean formations

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3779914A (en) * 1971-05-20 1973-12-18 Dow Chemical Co Composition of improved viscosity control and method of use
US3818991A (en) * 1971-05-20 1974-06-25 Dow Chemical Co Method of treating subterranean formation with a composition of improved viscosity control
US3760881A (en) * 1971-05-24 1973-09-25 Exxon Production Research Co Treatment of wells with fluids containing complexes
US4202795A (en) * 1978-09-28 1980-05-13 Halliburton Company Methods and additives for delaying the release of chemicals in aqueous fluids
US4436156A (en) * 1982-06-21 1984-03-13 Halliburton Company Method of treating well formations employing foamed treatment fluids
US4552675A (en) * 1983-08-19 1985-11-12 Fmc Corporation Composition and method for treating a subterranean formation
US4506734A (en) * 1983-09-07 1985-03-26 The Standard Oil Company Fracturing fluid breaker system which is activated by fracture closure
US4741401A (en) * 1987-01-16 1988-05-03 The Dow Chemical Company Method for treating subterranean formations

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0677642A2 (fr) * 1994-04-12 1995-10-18 Halliburton Company Procédé pour la rupture de fluides viscosifiés dans un puit de pétrole
EP0677642A3 (fr) * 1994-04-12 1995-11-08 Halliburton Co

Also Published As

Publication number Publication date
BR9001977A (pt) 1991-07-30
NO901934L (no) 1990-11-02
AU5399590A (en) 1990-11-01
NO901934D0 (no) 1990-04-30

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